1. Field of the Invention
The present invention relates to a drum tightening frame used in, for instance, bass drums, snare drums and marching drums and more particularly to a structure for mounting a tightening frame on a drum body.
2. Prior Art
In drums such as bass drums, snare drums, and marching drums, the drumheads are supported and tensioned by a plurality of head supporting and tensioning assemblies, and a specified tensile force is applied to the drumheads.
FIG. 5 shows a conventional snare drum (upside-down), and FIG. 6 shows the essential portion of the head supporting and tensioning assembly of the drum.
The reference numeral 1 is a drum main body that is cylindrical and opened at both ends. The reference numeral 2 refers to drumheads (2a and 2b), and 3 refers to a head supporting and tensioning assembly for the drumheads 2.
The head supporting and tensioning assembly 3 is comprised of an annular head frame 5, which is mounted on the external surface of the drum main body 1, and an annular tightening frame (rim) 6, which is likewise mounted on the external surface of the drum main body 1. The head supporting and tensioning assembly 3 further includes a plurality of lugs 7, which are fastened to the external surface of the drum main body 1, and tightening bolts 8, which connect the respective lugs 7 and the tightening frame 6.
With the structure above, the drumheads 2 are adjusted, in other words, the tone color of the snare drum 10 is adjusted, by turning the tightening bolts 8 with a tuning key (not shown) so that the tightening frame 6 is pressed against the head frame 5, thus moving the head frame 5 in the axial direction of the drum main body 1.
In FIGS. 5 and 6, the reference numeral 2a refers to the drumhead on the front (or top) side, 2b refers to the drumhead on the back (or bottom) side of the drum, and 9 refers to snappies (acoustic wires) disposed on the back side drumhead 2b. In addition, the reference numeral 16 is a washer. A plurality of washers 16 are respectively disposed between the tightening bolts 8 and the tightening frame 6.
Typically, the tightening frame 6 is made of a metal consisting of a molded product such as aluminum, etc., and it is formed so as to have an L-shaped cross section, as best seen from FIG. 6, so that the tightening frame 6 includes a cylindrical portion 6A and a ring-form circular plate portion 6B. The cylindrical portion 6A has a diameter that is larger than the external diameter of the drum main body 1 but smaller than the external diameter of the head frame 5. The ring-form circular plate portion 6B is integrally formed with the cylindrical portion 6A, and it circumferentially extends outward at the lower end (in FIG. 6) of the cylindrical portion 6A.
A plurality of bolt attachment openings 11 are opened in the circular plate portion 6B (only one opening 11 is shown in FIG. 6) so that they positionally correspond to the respective lugs 7. Each bolt attachment opening 11 is typically round in shape, and its hole diameter is slightly larger than the external diameter of the shank 8A of the tightening bolt 8 and is slightly smaller than the diameter of the head 8B of the tightening bolt 8. The shank 8A has an externally threaded screw section 12. The bolt attachment opening 11 can be of a slot type as shown in FIG. 7. The slot type bolt attachment opening 11 extends along the external surface of the tightening frame 6xe2x80x2 and has an arc-shape and opened at one end.
However, the above-described convention drum tightening frames 6 and 6xe2x80x2 have problems.
In tightening frame 6 shown in FIG. 6, the heads 8B of the tightening bolts 8 cannot pass through the bolt attachment openings 11 of a round shape (since the hole diameter of each bolt attachment opening 11 is smaller than the head 8B). As a result, when the drumhead 2 is to be replaced, the tightening bolts 8 must be removed from the lugs 7 (more specifically, from the lug nuts 15 of the lugs 7), and then the tightening frame 6 and head frame 5 are removed from the drum main body 1. When the drumhead 2 is to be mounted, the head frame 5 and tightening frame 6 are first mounted on the drum main body 1, after which the tightening bolts 8 are passed through the bolt attachment openings 11 and screwed into the lug nuts 15 of the lugs 7, and then the tightening frame 6 and lugs 7 are connected by the tightening bolts 8. Such attachment and removal of the tightening bolts 8 is, however, bothersome, since the number of the tightening bolts used is relative large. Thus, a considerable amount of time is required for attaching and replacing the drumhead 2.
In the case of the tightening frame 6xe2x80x2 shown in FIG. 7, the tightening frame 6xe2x80x2 is turned by a specified angle so that all the tightening bolts 8 are positioned outside the slots 13, and then the tightening frame 6xe2x80x2 is removed from the tightening bolts 8. Accordingly, there is no need to remove the tightening bolts 8 from the lugs 7, and attachment and replacement of the drumheads 2 is easier than in the tightening frame 6 of FIG. 6. The tightening frame 6xe2x80x2 thus has a better drum handling characteristics. However, each one of bolt supporting portions 14 (that have a xe2x80x9cJxe2x80x9d shape when viewed from above as seen from FIG. 7) that form the outside edges of the slots 13 is in a cantilever supporting structure. Accordingly, the bolt supporting portions 14 tend to flex when the tightening bolts 8 are tightened, making it difficult to give a desired tension to the drumhead 2. Especially in cases where high-tension tuning is performed, the bolt supporting portions 14 are more likely to bend or to be damaged, thus having problems in terms of strength.
Furthermore, in cases where washers 16 are respectively disposed between the heads 8B of the tightening bolts 8 and the ring-form circular plate portion 6B of the tightening frame 6 when the drumheads 2 are to be replaced, the tightening bolts 8 must be removed from the lugs 7, and then the tightening frame 6 and head frame 5 are removed from the drum main body 1.
More specifically, when one of the drumheads 2 is to be replaced, it is necessary to disengage the tightening bolts 8 from the lugs 7 and then to remove the tightening frame 6 and head frame 5 from the drum main body 1. When, on the other hand, the drumhead 2 is to be mounted, it is necessary to mount the head frame 5 and tightening frame 6 on the drum main body 1, pass the tightening bolts 8 through the bolt attachment openings 11 with washers 16 interposed and then screw the tightening bolt 8 to the lug nuts 15 of the lugs 7 so that the tightening frame 6 is pressed against the head frame 5.
However, if the washers 16 slip off of the tightening bolts 8 and drop when the tightening bolts 8 are removed from the lug nuts 15 and pulled out of the bolt attachment openings 11 in the tightening frame 6 at the time of attachment or replacement of the drumhead 2, the washers 16 are likely to be lost. In other words, the washers 16 would roll across the floor and enter small spaces between musical devices, furniture, etc. Accordingly, a careful attention is required in the attachment and removal of the tightening bolts 8.
The present invention solves the above-described problems with conventional drums, and it is an object of the present invention to provide a drum tightening frame that allows easy attachment, stretching and removal of drumheads.
It is another object of the present invention to provide a drum tightening frame that maintains a sufficient strength even in the case of high-tension tuning and holds the drumheads with appropriate tension in a stable fashion.
It is still another object of the present invention to provide a drum tightening frame that prevents loss of washers by preventing the washers from falling off of the tightening bolts or tightening frame when the tightening bolts are removed from the tightening frame.
The above objects are accomplished by a unique structure for a tightening frame for a drum in which the tightening frame is mounted on an open end of a drum body of the drum having a plurality of lugs on its outer surface, presses a head frame for the drum by being connected to the lugs via tightening bolts, and has an integrally formed circular plate portion; and in the present invention, the circular plate portion is provided with elongated bolt attachment openings with both ends thereof closed, and each of the bolt attachment openings is comprised of: a primary opening section that extends in a circumferential direction of the tightening frame and through which only the shank of a corresponding tightening bolt can pass, and a secondary opening section that is continuously formed at one end of the primary opening section and allows the head (and the shank) of the tightening bolt to pass through.
With this structure, when the tightening frame is turned by a specified angle so that the heads of the tightening bolts are brought into the secondary opening sections, the tightening frame can be removed from the tightening bolts, and this can be done without removing the tightening bolts from the lugs. Since each of the bolt attachment openings is in an elongated or slot shape that has closed ends, the bolt attachment portion of the tightening frame in which the bolt attachment opening is formed has a sufficient rigidity, and the bolt attachment portion can sufficiently withstand eve high-tension tuning.
The above objects are further accomplished by a unique structure of the present invention in which the washers and the tightening frame or the tightening bolts are formed so as to be magnetically attracted to each other.
By way of magnetically attaching the washers and the tightening frame or tightening bolts to each other, even in cases the tightening bolts are disengaged from the lugs and from the tightening frame, the washers will not fall off and thus can be prevented from being lost.
More specifically, the washer can be a magnetized magnetic material, and either the tightening frame or the tightening bolt is made of a magnetic material.
Instead, the washer can be made of a magnetic material, and either the tightening frame or the tightening bolt is made of a magnetized magnetic material.
It is also possible to form the washer with a magnetized magnetic material and to form one of the tightening frame and tightening bolt by a magnetized magnetic material and form another of the tightening frame and tightening bolt by a magnetized magnetic material.